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                Little Elephant and Boxes                </h1>
                <p>时间限制：10s&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;  空间限制：128MB</p>			</div>
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                                <h3>题目描述</h3><p><p><!--[if gte mso 9]><xml>
<w:LatentStyles DefLockedState="false" LatentStyleCount="156">
</w:LatentStyles>
</xml><![endif]--><b><span style="font-size:10.5pt;mso-bidi-font-size:11.0pt;font-family:宋体;mso-ascii-font-family:
Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:&quot;Cambria Math&quot;;
mso-font-kerning:1.0pt">利沃夫动物园的小象有</span><span lang="EN-US" style="font-size:
10.5pt;mso-bidi-font-size:11.0pt;font-family:Calibri;mso-fareast-font-family:
宋体;mso-bidi-font-family:&quot;Cambria Math&quot;;mso-font-kerning:1.0pt">n</span><span style="font-size:10.5pt;mso-bidi-font-size:11.0pt;font-family:宋体;mso-ascii-font-family:
Calibri;mso-hansi-font-family:Calibri;mso-bidi-font-family:&quot;Cambria Math&quot;;
mso-font-kerning:1.0pt">个盒子，每个盒子里有一些钱或者钻石。他不知道每个盒子里具体是什么，但他知道如果打开第</span><span lang="EN-US" style="font-size:10.5pt;mso-bidi-font-size:11.0pt;font-family:Calibri;
mso-fareast-font-family:宋体;mso-bidi-font-family:&quot;Cambria Math&quot;;mso-font-kerning:
1.0pt">i</span><span style="font-size:10.5pt;mso-bidi-font-size:11.0pt;
font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;
mso-bidi-font-family:&quot;Cambria Math&quot;;mso-font-kerning:1.0pt">个盒子，他有</span><span lang="EN-US" style="font-size:10.5pt;mso-bidi-font-size:11.0pt;font-family:Calibri;
mso-fareast-font-family:宋体;mso-bidi-font-family:&quot;Cambria Math&quot;;mso-font-kerning:
1.0pt">Pi / 100</span><span style="font-size:10.5pt;mso-bidi-font-size:11.0pt;
font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;
mso-bidi-font-family:&quot;Cambria Math&quot;;mso-font-kerning:1.0pt">的概率能获得</span><span lang="EN-US" style="font-size:10.5pt;mso-bidi-font-size:11.0pt;font-family:Calibri;
mso-fareast-font-family:宋体;mso-bidi-font-family:&quot;Cambria Math&quot;;mso-font-kerning:
1.0pt">Vi</span><span style="font-size:10.5pt;mso-bidi-font-size:11.0pt;
font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;
mso-bidi-font-family:&quot;Cambria Math&quot;;mso-font-kerning:1.0pt">美元的钱，而有</span><span lang="EN-US" style="font-size:10.5pt;mso-bidi-font-size:11.0pt;font-family:Calibri;
mso-fareast-font-family:宋体;mso-bidi-font-family:&quot;Cambria Math&quot;;mso-font-kerning:
1.0pt">(1 &ndash; Pi / 100)</span><span style="font-size:10.5pt;mso-bidi-font-size:
11.0pt;font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;
mso-bidi-font-family:&quot;Cambria Math&quot;;mso-font-kerning:1.0pt">的概率能获得一个钻石。现在有</span><span lang="EN-US" style="font-size:10.5pt;mso-bidi-font-size:11.0pt;font-family:Calibri;
mso-fareast-font-family:宋体;mso-bidi-font-family:&quot;Cambria Math&quot;;mso-font-kerning:
1.0pt">m</span><span style="font-size:10.5pt;mso-bidi-font-size:11.0pt;
font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;
mso-bidi-font-family:&quot;Cambria Math&quot;;mso-font-kerning:1.0pt">个物品，分别编号为</span><span lang="EN-US" style="font-size:10.5pt;mso-bidi-font-size:11.0pt;font-family:Calibri;
mso-fareast-font-family:宋体;mso-bidi-font-family:&quot;Cambria Math&quot;;mso-font-kerning:
1.0pt">0</span><span style="font-size:10.5pt;mso-bidi-font-size:11.0pt;
font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;
mso-bidi-font-family:&quot;Cambria Math&quot;;mso-font-kerning:1.0pt">到</span><span lang="EN-US" style="font-size:10.5pt;mso-bidi-font-size:11.0pt;font-family:Calibri;
mso-fareast-font-family:宋体;mso-bidi-font-family:&quot;Cambria Math&quot;;mso-font-kerning:
1.0pt">m &ndash; 1</span><span style="font-size:10.5pt;mso-bidi-font-size:11.0pt;
font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;
mso-bidi-font-family:&quot;Cambria Math&quot;;mso-font-kerning:1.0pt">，</span><span style="font-size:10.5pt;mso-bidi-font-size:11.0pt;font-family:Calibri;
mso-fareast-font-family:宋体;mso-bidi-font-family:&quot;Cambria Math&quot;;mso-font-kerning:
1.0pt"> </span><span style="font-size:10.5pt;mso-bidi-font-size:11.0pt;
font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;
mso-bidi-font-family:&quot;Cambria Math&quot;;mso-font-kerning:1.0pt">第</span><span lang="EN-US" style="font-size:10.5pt;mso-bidi-font-size:11.0pt;font-family:Calibri;
mso-fareast-font-family:宋体;mso-bidi-font-family:&quot;Cambria Math&quot;;mso-font-kerning:
1.0pt">j</span><span style="font-size:10.5pt;mso-bidi-font-size:11.0pt;
font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;
mso-bidi-font-family:&quot;Cambria Math&quot;;mso-font-kerning:1.0pt">个物品需要花费恰好</span><span lang="EN-US" style="font-size:10.5pt;mso-bidi-font-size:11.0pt;font-family:Calibri;
mso-fareast-font-family:宋体;mso-bidi-font-family:&quot;Cambria Math&quot;;mso-font-kerning:
1.0pt">Cj</span><span style="font-size:10.5pt;mso-bidi-font-size:11.0pt;
font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;
mso-bidi-font-family:&quot;Cambria Math&quot;;mso-font-kerning:1.0pt">美元的钱和</span><span lang="EN-US" style="font-size:10.5pt;mso-bidi-font-size:11.0pt;font-family:Calibri;
mso-fareast-font-family:宋体;mso-bidi-font-family:&quot;Cambria Math&quot;;mso-font-kerning:
1.0pt">Dj</span><span style="font-size:10.5pt;mso-bidi-font-size:11.0pt;
font-family:宋体;mso-ascii-font-family:Calibri;mso-hansi-font-family:Calibri;
mso-bidi-font-family:&quot;Cambria Math&quot;;mso-font-kerning:1.0pt">个钻石。小象非常聪明，当他获得了一定量的钱和钻石后，他总会买尽可能多的物品。注意，每个物品只能购买一次。现在请你帮助小象计算出，当他打开所有的盒子后，他期望能够买到的物品个数是多少？</span><span lang="EN-US" style="font-size:10.5pt;
mso-bidi-font-size:11.0pt;font-family:Calibri;mso-fareast-font-family:宋体;
mso-bidi-font-family:&quot;Cambria Math&quot;;mso-font-kerning:1.0pt"><br />
</span></b></p></p><hr/><h3>输入格式</h3><p><p>输入的第一行包含一个正整数T，表示数据组数。<br />
对于每组数据，第一行包含两个正整数n, m，分别表示盒子数与物品数。接下来n行，每行为两个整数Vi, Pi，分别表示小象能从第i个盒子中获得钱的数量与获得钱的概率。接下来m行，每行为两个整数Cj, Dj，分别表示第j个物品所需要的钱和钻石的数量。</p></p><hr/><h3>输出格式</h3><p><p>输出总共T行。每行为一个实数，为对应的测试数据的答案，实数四舍五入保留到小数点后4位。</p></p><hr/><h3>样例输入</h3><pre>2
2 2
2 50
2 100
2 0
2 0
2 2
2 100
2 50
0 2
0 1</pre><hr/><h3>样例输出</h3><pre>1.5000
0.5000</pre><hr/><h3>提示</h3><p><p>1&le;T&le;5,&nbsp;&nbsp; 2&le;n&le;30,&nbsp;&nbsp; 1&le;m&le;30<br />
<br />
1&le;Vi, Cj&le;107,&nbsp;&nbsp; 0&le;Dj&le;30,&nbsp;&nbsp; 0&le;Pi&le;100<br />
<br />
&nbsp;</p></p><hr/><h3>题目来源</h3><p>没有写明来源</p>
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